I'm running on a couple year old computer but it's been rock solid for me, but it comes a time to do some minor tweaking to meet with the rising demands of my addiction.

Which is going to get me the bigger upgrade on my system specifically for WoW? Upgrading the processor or adding an SSD to host wow on?

Machine Specs:
BFG GeForce 8800 GTS / 640MB / PCIe
Intel Core 2 Duo e6300 - 1.86Ghz / 2MB Cache / 1066 FSB
4 GB 667 Mhz Ram
2x500g SATA Hard Drives in Raid 0
WinXP Pro

The motherboard supports up to the q6700 - 2.66ghz Quad Core 8 MB Cache 10066 FSB which would be a significant upgrade.

But would I get more of a efficiency increase from switching to running WoW off an SSD? Considering the price is roughly the same (with the SSD being slightly more) for each of these different upgrades.

I'm currently 4 boxing on a single 22" monitor and am borderline with throwing in a 5th to start 5 boxing and kicking to a dual monitor setup. I keep dropping my graphics down further and further as I get to higher end content. Hellfire wasn't bad, but Zangermarsh is kicking my computers ass. Using HKN and trying to switch screens is painfully slow.